Electrical Engineering ⇒ Topic : Electromagnetic Induction
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Gaurav
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Electromagnetic Induction When the magnetic flux *linking a conductor changes, an e.m.f. is induced in the conductor. If the conductor forms a complete loop or circuit, a current will flow in it. This phenomenon is known as **electromagnetic induction. The phenomenon of production of e.m.f and hence current in a conductor or coil when the magnetic flux linking the conductor or coil changes is called electromagnetic induction
figure (a) To demonstrate the phenomenon of electromagnetic induction, consider a coil C of several turns connected to a centre zero galvanometer G as shown in Fig.(a). If a permanent magnet is moved towards the coil, it will be observed that the galvanometer shows deflection in one direction. If the magnet is moved away from the coil, the galvanometer again shows deflection but in the opposite direction. In either case, the deflection will persist so long as the magnet is in motion. The production of e.m.f. and hence current in the coil C is due to the fact that when the magnet is in motion (towards or away from the coil), the amount of flux linking the coil changes the basic requirement for inducing e.m.f. in the coil. If the movement of the magnet is stopped, though the flux is linking the coil, there is no change influx and hence no e.m.f. is induced in the coil. Consequently, the deflection of the galvanometer reduces to zero. | |
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